The proposed research is designed to investigate the arrangement of specific gustatory inputs to the nervous system within the receptor array. The immediate objective is to understand the distribution of amiloride- and gurmarin-sensitive transduction mechanisms across taste receptor cells (TRCs) located in both the fungiform and palatal epithelia. Toward achievement of these aims, an experimental paradigm was chosen that allows transmembrane currents to be patch recorded from the basolateral membrane of individual TRCs in situ following taste stimulation that is restricted to the mucosal surface. Thus, this procedure permits one to chemically stimulate TRCs in a manner that is representative of how these cells would naturally interact with taste stimuli, which provides an unbiased method for measuring the tuning profiles of TRCs. Moreover, this preparation is ideally suited for determining the influence of both amiloride and gurmarin on the gustatory sensitivities of individual TRCs. When coupled with what is known regarding the effects of these substances on higher-order neuronal elements, data obtained from the proposed experiments may logically reveal the existence of specific synaptic links between particular types of TRCs and nerve fibers that express common sensitivity shifts following specific gustatory input blockage.